Carbon capture is defined as capturing carbon dioxide at the point of emission or from the atmosphere, either indirectly or directly. At this point, carbon is separated from other gases, transported, and then later buried or stored in a suitable deep, underground place.
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In 2010, worldwide carbon dioxide emissions from fossil fuels were around 32 Gigatons. Industrial operations and stationary emission sources such as cement manufacturing, power plants, and refineries are responsible for producing carbon dioxide in the atmosphere.
Between 1750 and 2010, approximately 50% of the overall anthropogenic carbon dioxide emissions have been generated in the previous 40 years.
Types Of Carbon Capture
Pre-combustion carbon capture
Pre-combustion carbon procedures involve trapping carbon before the combustion process of fossil fuels ends. Synthesis syngas or gas is produced when oil, coal, or natural gas is heated in oxygen and steam.
The gas is composed of carbon dioxide, carbon monoxide, and hydrogen. The reaction subsequently turns water into hydrogen. During this process, carbon monoxide is converted into carbon dioxide. The final result is a gas with a mixture of carbon dioxide and carbon dioxide is produced. The mixture can be trapped, separated, and sequestered from the mixture. The hydrogen can be utilized for other energy generation operations.
Pre-combustion carbon capture is often more efficient and effective compared to post-combustion carbon capture. The equipment is more expensive than other processes.
Post-combustion carbon capture
During the combustion of fossil fuels, carbon dioxide is captured. The combustion of fossil fuels emits flue gases, which contain sulfur dioxide, nitrogen, water vapor, carbon dioxide, and nitrogen.
Carbon dioxide is collected and isolated from the flue gases generated from the combustion of fossil fuels in a post-combustion process. Post-combustion capturing is the most utilized carbon-capture technology. This is because of its ability to be utilized in both new and existing coal-fired power plants. This process does pose some challenges, namely that it requires massive equipment to function which can affect the efficiency of the turbines.
Oxy-fuel combustion carbon capture
Regular air is not utilized during the combustion of fossil fuels. Instead, a mixture of high concentrations of pure oxygen is utilized during the combustion process.
Water and carbon dioxide are the primary components of the flue gas produced during the combustion process. By compressing and cooling the flue gas, it is feasible to separate the carbon dioxide in the gas.
One of the benefits of oxy-fuel combustion capture is that it can be utilized in both new and existing coal-burning plants. The process on the whole is relatively expensive, though certain components are generally inexpensive.
Advantages of Carbon Capture
Carbon capture and storage is one of the most efficient methods of extracting carbon emissions permanently from the environment.
The numerous advantages of CCS include economic, social, and environmental, and a massive impact on a global and local scale.
Carbon capture can increase the power generated with carbon dioxide-based steam cycles. In this process, carbon dioxide is pressured through a supercritical fluid, which could transfer heat more effectively and require less energy to compress steam.
Geologically stored carbon dioxide might be utilized to retrieve geothermal heat from the area injected which results in the generation of sustainable geothermal energy.
Carbon dioxide captured with carbon capture can also be utilized in the manufacturing of polymers and chemicals such as polyurethanes.
The captured carbon dioxide is incorporated into concrete to reinforce it and increase the durability of the infrastructure. The carbon capture operations create employment for skilled engineers and technicians who need to operate them.
Disadvantages of Carbon Capture
Carbon capture reduces the carbon released in the atmosphere and therefore, it is recognized as one of the solutions to help address climate change and global warming. Despite this, carbon capture and storage (CCS) does not come without some disadvantages.
The methods and CCS technologies that are necessary for carbon capture have some cost implications attached to them. Therefore, it can be very costly for power plants to generate electricity through fossil fuels. There are several concerns with respect to the safety of the storage of carbon dioxide in huge volumes at a single location due to the possibility of leakages, which can lead to environmental contamination if not handled correctly.
The possibility of leakages could also be a result of natural disasters such as earthquakes or can be a result of human-induced incidents such as damage as a result of wars that can damage underground storage reservoirs.
Many critics have questioned the cost efficiency of basalt formation storage. For this option, 25 tons of water will be required for each ton of carbon dioxide to be buried. There is a possibility that volcanic rock microbes can also digest the carbonates and hence produce methane gas which can be another problem.
Another disadvantage of carbon capture storage is that it is not adequate to successfully deal with climate change. The emissions that come from heat and power generation as a result of using fossil fuels only account for about 25% of the total greenhouse gas (GHG) emission, while 60% of all greenhouse gas emissions come from transportation, agriculture, and other related industrial activities. These emissions are currently not being captured by carbon capture and storage.
The Future of Carbon Capture
The transit to energy sources that generate minimal or no greenhouse gases must be made. However, we should address the ever-increasing carbon emission industries.
Sequestered carbon can become a vital instrument of global climate strategy if the carbon capture sectors continue to innovate and expand. Carbon capture technologies should be developed and scaled up to make them commercially feasible.
References and Further Reading
Ronca, D. and Mancini, M., 2021. How Carbon Capture Works. [online] HowStuffWorks. Available at: https://science.howstuffworks.com/environmental/green-science/carbon-capture.htm
Nationalgrid.com. 2022. What is Carbon Capture and Storage? | National Grid Group. [online] Available at: https://www.nationalgrid.com/stories/energy-explained/what-is-ccs-how-does-it-work
bgs.ac.uk. 2022. Understanding carbon capture and storage. [online] Available at: https://www.bgs.ac.uk/discovering-geology/climate-change/carbon-capture-and-storage/
Border States. 2022. 5 potential benefits of carbon capture and storage (CCS) technology. [online] Available at: https://solutions.borderstates.com/benefits-of-carbon-capture-and-storage/
Williams, F., 2019. Pros and Cons of Carbon Capture and Storage - Konsyse. [online] Konsyse. Available at: https://www.konsyse.com/articles/pros-and-cons-of-carbon-capture-and-storage/
Borealis, S., 2021. The future of carbon: capture, storage, sequestration, re-use. [online] scienceborealis.ca Blog. Available at: https://blog.scienceborealis.ca/the-future-of-carbon-capture-storage-sequestration-re-use/